The present invention relates to single sheet feeding from a stack of sheets into a printer whereby particularly a feed channel is associated with a printing platen, and the feeding is carried out under utilization of driven transport rollers, a stack bottom being movable with respect to these rollers and including further stops for the stack as well as single sheet separating fingers.
Equipment for single sheet feeding including features for separating the individual sheets from a stack are, for example, used in a variety of printers and here, particularly, printers of the matrix variety. German printed Pat. No. 29 28 353 discloses, for example, to arrange transport rollers such that they establish a clamping gap for the sheet to be moved whereby the transport rollers are drivingly connected to the platen under utilization of a slip clutch. The finger singling out individual sheets is associated with that gap and there are operating elements for this finger which include a cam disk being slip free connected to the platen drum. These actuating elements include further a scanning lever cooperating with the aforementioned cam disk and acting upon the sheet singling finger accordingly. The transport rolls are spaced in relation to the transport equipment generally and in relation to the platen drum such that the advanced sheet is in engagement simultaneously with a sheet separating transport roller as well as with those transport rollers which establish the clamping gap, or with the platen drum.
The known equipment as described uses furthermore a movable bottom or platform for the stack of sheets which is spring biased and therefore urges the sheets against the separating rollers. This kind of arrangement does not exclude the possibility that the stack bottom urges more than one sheet by operation of the spring force so that the singling or separating roll in fact advances two sheets which are now shifted together against the sheet separating finger. Moreover, this known equipment provides this finger merely as a stop and the finger is not actually used for separating individual sheets in the range of the stack bottom.